The clearest ocean waters on Earth

As clear as the clearest lakes on the planet, salty as ocean waters, and roughly the size of the Mediterranean – this, say researchers, is the clearest and most lifeless patch of ocean in the world. And it is in the middle of the Pacific.

Marc Tedetti, from the University of the Mediterranean, was on the expedition to investigate the water's clarity. He was struck by the colour of the water, which he describes as closer to violet than to blue.

At the clearest point of the south-east Pacific, near to Easter Island, Tedetti found that UV rays could penetrate more than 100 metres below the surface.

This correlates with Raimbault's chlorophyll measurements, which suggest the patch contains roughly 10 times less chlorophyll that is found in most ocean waters.

Raimbault says the patch of ocean is the least productive marine region known to man.